xlSQL is a JDBC Driver for Excel, CSV, and other document data sources. Documents can be read and written with SQL as if they were tables in a database. In the case of Excel, xlSQL maps a directory with Excel files to a database, workbooks to schemas, and sheets to tables. These tables can be queried with the full SELECT syntax of either the HSQLDB, MySQL, or McKoi SQL dialect. Native xlSQL is a rich subset of SQL for creating, altering, and populating documents.